Skip Marshall was born in Columbus, Ohio and received both his undergraduate degree and law degree from The Ohio State University. Prior to entering law school, Skip was a firefighter on the Columbus, Ohio Fire Department. After graduating from law school, Skip became an Assistant to the Prosecuting Attorney of Franklin County (Columbus), Ohio.

In 1985, Skip moved to Southern California. After working several years as corporate counsel and associate attorney in the litigation section of a major law firm, Skip decided to dedicate his legal skills to criminal law. In 1992, Skip became a Los Angeles County Deputy District Attorney, and later he transferred to a position as a Los Angeles County Deputy Public Defender.

In 2018, after more than 25 years of service for the County of Los Angeles, Skip retired from government service and founded the Marshall Criminal Defense Law Firm.